A service provider, e.g. providing a media streaming service, may provide the service via either or both of a web application on a web site of the service provider and a service application (app/client) installed on a user device such as a smartphone. A user may be logged into the service via the web site and/or via the app. The user may even be logged in via the web site from the same smartphone which has the app installed thereon, by means of a web browser installed on the smartphone. The user may e.g. be continuously logged in via the app (since there may be no reason to log out from the service since the smartphone is only used by the user) while only occasionally logging in via the web site (for instance for performing payments or the like which is not supported via the app). The user than has to remember his/her user name and password, and log in also via the web site.